Pulpwood soaking device



July 19, 1955 B. SUCKSDORFF 2,713,346

PULPWOOD SOAKING DEVICE Filed Sept. 25, 1952 IN VEN TOR.

U fi tates Paten 2,713,346 PULPWOOD SOAKILJG DEVICE Bjorn Sucksdortf,Kuusankoski, Finland Application September 25, 1952, Serial No. 311,383

11 Claims. (Cl. 134-107) This invention relates to improvementsin'pulpwood soaking devices for use in wetting pulpwood effectivelyprior to barking.

Pulpwood is, in the main, either floated or transported by land to itsplace of use.

A part of the bark and sapwood might already then have been removedtherefrom.

The moisture content thereof varies and depends on the transportationmethod adapted, age of cut tree and storage facilities.

Prior to using pulpwood it is necessary in most cases to strip all theremaining bark therefrom so as to obtain a pure end-product, a purechemical pulp, mechanical pulp or paper.

If the pulpwood is moist and especially if same is floated, the barkstrips off easily. But should the pulpwood have dried in the woods andis, e. g. half peeled or strip barked, the bark sticks hard to the log.

Previously, cut trees were barked at their place of use by means ofknife barkers which stripped from the surface of the tree appreciableamounts of wood besides bark. Thus wood losses were appreciably greatbut the barked log was very clean. To reduce material losses knifebarkers were replaced by means using other barking methods such as e.g., rotating barking drums, chain barkers or hydraulic barkers. Allthese means and methods have for their object to strip off bark withoutdamaging the wood material. Then too, it is naturally of first-rateimportance that the bark sticks as loosely as possible to the cut treeor log.

Should dry wood with dried bark strongly adhering thereto be barked e.g., in barking drums unduly long periods of time are required for theoperation partly for the reason that the dark must be soaked in waterfor so long a time as to give it a moisture content adequately high toenable the bark to loosen readily, partly for the reason that dry barkrequires more vigorous mechanical treatment than does moist bark. Itfollows that machines must be large in size and expensive and that thelogs will, in consequence of barking operations of long duration, besubjected for a longer time to high mechanical stresses which in turncause the ends of logs to wear out round and form brushy splitters withconsequent losses in wood substance, increase in necessary power andappreciable wear and tear of the drums.

Practice has shown that the treatment time for wood fed dry into barkingdrums may even be seven times longer than that for wet or efficientlysoaked wood.

However, the soaking of wood is no simple operation, and in differentplaces it might be effected in very many ways.

The simplest way is to keep the wood in large ponds, lakes or watercourses. For reducing necessary storage space the wood is stored inbundles. This, however, requires much Work and if it is desired to soakthe part floating above water level also, the bundles must be turned orarrangements made for continuously spraying water over the wood or logbundles. The whole treatment 2,713,345 Patented Judy 19, 1955 icerequires much space, is expensive and especially in winterdisadvantageous.

Another method of soaking wood comprises the filling of soaking chambersor soaking towers with the wood, which is prevented from floating upwhen water is being admitted into the said chambers or towers. Also thismethod is expensive because of its periodicity.

A third method comprises submerging the Wood into water, in a longsoaking pond by means of wide, matlike conveyors. However, such deviceshave not been successful in soaking woods longer than 2 feet, becauselonger woods in disorder easily jam the soaking channel.

Moreover, there are prior known methods according to which the wood isarranged in parallel bundles, which are placed into short soaking pondsand submerged in water by means of a large rotating drum. Theconstruction of the soaking ponds and towers hereinabove describedrenders possible the use of warm water therein, but the higher the watertemperature rises the greater will be the operation difficulties becauseof evaporation and mist formation.

It is the object of this invention to provide a pulpwood soaking devicewithout the defects hereinabove described.

An object of the invention is to provide a soaking device through whichthe pulp wood to be treated is fed as a continous pile in such a waythat the shape of the pile is not altered and no relative movementoccurs between the logs.

Another object of the invention is to provide a pulp Wood soaking devicehaving means for automatically stopping the feeding of pulp wood intothe said soaking device should the wood in the pile become disarranged.

Still another object of the invention is to provide a pulp wood soakingdevice having means for regulating the temperature of the water andmeans for efiectively circulating same in countercurrent to the movementof the Wood.

And still another object of the invention is to provide a pulp woodsoaking device having means for regulating the speed of feeding the woodas also the amount of wood to be fed through said device.

The foregoing and other objects of this invention will be apparent fromthe following specification, taken in con nection with the accompanyingdrawing wherein a preferred embodiment of the invention is shown.

In the drawing:

Fig. 1 is a schematic side elevation of the soaking device madeaccording to this invention.

Fig. 2 is an enlarged, sectional view taken along line A--A of Fig. l,and

Fig. 3 is an enlarged, sectional view taken along line B-B of Fig. 1.

The principal parts of the device shown in the drawing are:

A long water-filled channel 1, open at both ends thereof.

A conveyor 2, hereinafter to be termed supply conveyor adapted to feedwood into the channel as a continous pile.

A conveyor 3, hereinafter to be termed transfer conveyor having a speedapproximately equal to that of the first-mentioned conveyor and adaptedto press the wood under water and convey the same through the channel.

A conveyor 4, hereinafter to be termed withdrawal conveyor and adaptedto lift the soaked wood away from the channel to be transported tosubsequent treatments, and

Pumps 11, 15 for circulating the water and heat exchangers 13 forheating the water.

The channel 1 is curved so that the ceiling and bottom parts thereof areshaped to form concentric cylinder parts having very great radii and anaxis located above the said channel and at right angle to thelongitudinal axis of the channel. At the supply end the bottom of thechan nel is recessed to accommodate the supply conveyor 2 zhich is alsocurved to form a cylinder part concentric with the channel. The supplyconveyor 2 includes a plurality of endless chains arranged side by sideand having fixed thereto suitable gripping members. Both ends of thesupply conveyor 2 and consequently the whole conveyor, can be raised andlowered at will with lifting means schematically shown by arrows 5.

The transfer conveyor 3 is so arranged that while the forward movingpart thereof runs along the ceiling the rearward moving part runs abovethe channel. The conveyor itself includes a plurality of chains (sevenin the drawing) having fixed thereto transversely disposed catchers.These catchers have a threefold function: firstly they sink between thelogs and thereby pull the pile forward, secondly they run in grooves 9made in both upper corners of the channel and thus keep the chainscorrectly in place also when the channel is empty, and thirdly they givesupport to the chains on the return side. To prevent the chains fromwearing out, they are placed between longitudinal rails 16 in thechannel roof allowing the catchers and uppermost logs in the pile tocontact the rails. To prevent breaking in the case that too high a pileis fed between the conveyors 2 and 3, the supply end 6 of the conveyor 3is mounted turnable on hinges 7.

The supply conveyor 2 and transfer conveyor 3 derive their movementsfrom suitable power sources, e. g., electric motors not shown in thedrawing. These two conveyors run with substantially one and the samespeed which is proportional to the curvature radii, the two speeds beingadvantageously adapted to be regulated simultaneously and in the sameratio.

On both sides of the supply opening of the channel I. are arranged bars8 which, when hit by a log, will cut off the current to the motors ofthe conveyors 2 and 3 and thereby cause said conveyors to stop. Thus thechannel is prevented from becoming jammed should the logs be sidewisedisarranged on arriving at the supply opening of the channel.

At the discharge end of the channel 1 is arranged the withdrawalconveyor 4 comprising a plurality of endless chains with thereto rigidlysecured gripping means and adapted to be run by a motor not shown on thedrawing at a speed slightly greater than those of the conveyors 2 and 3.Also the withdrawal conveyor 4 is curved concentrically with thecurvatures of the channel 1 and the supply conveyor 2 and the transferconveyor 3. Underneath the withdrawal conveyor 4 is arranged a suitableconveyor, e. g., a band conveyor for receiving the falling logs.

For circulating water in the channel 1 and for heating same a screen 10is arranged beneath the supply conveyor 2 to permit passage of watertherethrough into a tank 13 wherefrom it is forced by means of the pump11 via pipe line 1.9, heat exchanger 13 and one or more pipes 14 passedthrough the channel ceiling into the discharge end of the channel 1. Bymeans of the heat exchanger the water can be heated to the temperaturedesired. Moreover, two pumps 15 are arranged in the channel to suckwater from the side walls or bottom of the channel and then force it viathe pipes 20 back into the channel through the ceiling thereof. Thuswater circulates in countercurrent to the movement of the wood.

For removing bark and other impurities carried by the water to thescreen 10 there is arranged one or more scraping means 12 for cleaningthe screen 19 continuously.

The device operates as follows:

Wood is piled manually or by means of a lifting device into an endlesspile upon the supply conveyor 2 which continuously feeds the pileforward and downward. As the pile runs into water the downward pressuregradually decreases until the water has risen so high that the wholepile floats. Then the upper part of the pile comes into contact with thetransfer conveyor 3 which continues the forward movement while forcingthe whole pile under water. Should the shape of the pile change in thisphase and the logs in the pile move relative to each other it mayhappen-especially if the logs are crookedthat they push themselvestowards the sidewalls of the channel. Should this happen, the wholechannel will soon jam up. According to the invention no changes in theshape of the pile will occur partly because the channel itself, supplyconveyor 2 and transfer conveyor 3 are constructed so as to formconcentric cylinder parts having very big radii and an axis locatedabove the channel, and partly because the distance between the supplyconveyor 2 and the transfer conveyor 3 can be regulated by raising orlowering the conveyor 2 to suit the height of the pile. Moreover, thesupply end 6 of the transfer conveyor 3 may turn about the hinges 7.Should a log or two despite everything turn sidewise they would, in sodoing, hit the bars 8 which thereby cut off the current and stop themotors, after which it is possible to correct the positions of the logs,c. g. with a boat hook.

At the discharge end of the channel the pile frees itself of thetransfer conveyor 3 and the logs move towards the withdrawal conveyor 4having a speed greater than that of the two previously mentionedconveyors and adapted to lift the logs from the water and over thechannel threshhold onto the conveyor 17 adapted to transport the logsonward for further treatment.

It is important that all the logs are wetted and heated evenly. This isachieved in the claimed device wherein water heated to the desiredtemperature is fed in countercurrent flow to the movement of the logs.Water is pumped from the fore-end of the channel 1 via the heatexchanger 13 and onwards to the rear-end of the channel where it isforced into the channel through a pipe or pipes 14 between the rails 16in the ceiling. The rails serve as guides and prevent water from flowingsidewise, wherefore water penetrates down through the pile. There thewater cools down in consequence of which the downward flow through thepile becomes more effective. Because of the circulation pumps 15 whichsuck water from the bottom of the channel and force it down from betweenthe rails 16 in manner similar to that hereinabove described,circulation and soaking are as effective as possible. Hence, heating upand wetting occur gradually in the counter-current flow of logs andwater.

The period of time for soaking can be varied by running the conveyors 2and 3 at varying speeds. The pulp wood amount in the channel can bevaried thereby that the height of the pile is increased or decreased byraising or lowering the conveyor 2 and in addition to this soakingefiiciency can be increased or decreased by changing the watertemperature. Hence the device is suitable for use in treating differentkinds of wood intended for various end-products.

Although the invention has hereinabove been described with reference toa suitable embodiment given as an example only, it is apparent that suchconstructional modifications as are obvious to those skilled in the art,are to be construed as falling within the scope and spirit of thisinvention.

What I claim is:

1. Apparatus for soaking pulpwood comprising a long channel open at bothends thereof, the bottom of said channel being curved longitudinally andconvexly downwardly from its ends toward its intermediate position onthe arc of a circle having a long radius, a first conveyor means forcontinually feeding a pile of pulpwood into said channel, a secondconveyor means for transporting said pile of pulpwood through saidchannel, said second conveyor means extending in spaced relation withres ect to said bottom of said channel and on an are concentric withsaid are of said bottom, a third conveyor means for discharging saidpile of pulpwood from said channel, means for circulating water throughsaid channel and means for controlling the temperature of saidcirculating water.

2. Apparatus for soaking pulpwood comprising a long channel open at bothends thereof, the bottom of said channel being curved longitudinally andconvexly downwardly from its ends toward its intermediate position onthe arc of a circle having a long radius, a first conveyor means forcontinually feeding a pile of pulpwood into said channel, a secondconveyor means for transporting said pile of pulpwood through saidchannel, said second conveyor means extending in spaced relation withrespect to said bottom of said channel and on an are concentric withsaid arc of said bottom, a third conveyor means for discharging saidpile of pulpwood from said channel means for circulating water throughsaid channel in counter current to the movement of said pulpwood, andmeans for controlling the temperature of said circulating water.

3. Apparatus for soaking pulpwood comprising a long channel convexlydownwardly curved from its ends towards its intermediate position openat both ends thereof, said channel including a ceiling therealong theradius of curvature of said channel being large, a first conveyor meansat the one end of said channel for continually feeding a pile ofpulpwood into said channel, a second conveyor means located along saidceiling of said channel for transporting said pile of pulpwoodtherethrough, and a third conveyor means at the other end of saidchannel for discharging said pile of pulpwood from said channel, meansfor circulating water through said channel in counter current to themovement of said pulpwood, and means for controlling the temperature ofsaid circulating water.

4. Apparatus for soaking pulpwood as in claim 3, wherein bars areprovided on both sides of the supply opening of said channel, said barsbeing adapted to stop said first and second conveyor means whencontacted by a log in said pile of pulpwood.

5. Apparatus for soaking pulpwood comprising a long channel convexlydownwardly curved from its ends towards its intermediate position openat both ends thereof, said channel including a ceiling therealong theradius of curvature of said channel being large, a first conveyor meansat the one end of said channel for continually feeding a pile ofpulpwood into said channel, a second conveyor means located along saidceiling of said channel for feeding said pile of pulpwood therethrough,and

a third conveyor means at the other end of said channel for dischargingsaid pile of pulpwood therefrom, said first, second and third conveyormeans being curved concentrically with said channel, pumps forcirculating water through said channel in counter current to themovement of said pile of pulpwood, and a heat exchanger for controllingthe temperature of said circulating water.

6. Apparatus for soaking pulpwood as in claim 5, wherein said firstconveyor means are vertically adjustable.

7. Apparatus for soaking pulpwood as in claim 6, wherein the end part ofsaid second conveyor means adjacent said first conveyor means is hinged.

8. Apparatus for soaking pulpwood as in claim 7, wherein longitudinalrails are provided along said ceiling of said channel.

9. Apparatus for soaking pulpwood as in claim 7, including, means fordriving said first and second conveyor means at speeds, proportional tothe ratio of the radii of longitudinal curvature of the upper surface ofsaid first conveyor means and of the under surface of said secondconveyor means of curvature, means for driving said third conveyor meansat a higher speed than those of said first and second conveyor means.

10. Apparatus for soaking pulpwood comprising, a long channel convexlydownwardly curved from its ends towards its intermediate position openat both ends thereof, the radius of curvature of said channel beinglarge, a ceiling above said channel, a first conveyor means at one endof said channel for continually feeding a pile of pulpwood into saidchannel, a second conveyor means located along said ceiling of saidchannel for transporting said pile of pulpwood therethrough, a thirdconveyor means at the other end of said channel for discharging saidpile of pulpwood from said channel, means for circulating water throughsaid channel in counter current to the movement of said pulpwood, saidcirculating means including a pump for pumping water from the bottompart of the supply end of said channel to the discharge end thereof andmeans for discharging said water through said ceiling back into saidchannel, and pumps for pumping water from the bottom part of saidchannel to points near the supply end thereof and discharging the samethrough said ceiling, and means for controlling the temperature of saidcirculating Water.

11. Apparatus for soaking pulpwood comprising a long channel convexlydownwardly curved from its ends towards its intermediate position openat both ends thereof, said channel having a bottom, side walls and aclosing top opposite said bottom, said channel being curved on an arc ofa circle having a long radius, said channel being filled with water whensaid apparatus is in use, and conveyor means for conveying a pile ofpulpwood into, through and out of said channel without changing theshape of said pile, said conveyor means including a conveyor extendingalong said channel beneath the top of the same, said conveyor beingcurved concentrically with said curvature of said channel.

References Cited in the file of this patent UNITED STATES PATENTS1,475,198 Potthofi Nov. 27, 1923 2,057,982 Secondo Oct. 20, 19362,143,838 Boettger Jan. 17, 1939 2,249,792 Skinner July 22, 19412,580,420 Griswold Jan. 1, 1952 FOREIGN PATENTS 20,065/34 Australia Nov.8, 1934

